Press

ABSTRACT

This disclosure relates to a press of the type provided with aligned plungers arranged to successively form a workpiece and having driving and restoring cams arranged to actuate the plungers through a crank mechanism having arms arranged in predetermined angular relationship and in engagement with the cams at all times.

United States Patent 1 3,596,498

[72] Inventor Charles R. Bradlee 2,150,890 3/1939 Franghia i i 72/405 Cheshire, Conn. 3,383,929 5/1968 Grutter 1. 74/53 [211 Appl Noi 787,493 242,772 6/1881 Halkyard 72/405 [22] Filed Dec. 27. I968 2.317.740 4/1943 Devlin 2 74/567 Patented Aug-3. 197] 3,199,358 8/1965 Bradlee .7 72/452 [73] Assignee Textron. Inc. 3,369,387 10/1965 Bradlee 72/405 Providence. RJ. 3,358,591 12/1967 Bradlee 100/257 FOREIGN PATENTS 933 433 8/1963 Great Britain H 72/405 [54] PRESS a 12 Cum. n Dram": a 1.315 4/1868 Great Britain 7 /405 Primary Examiner-Charles W. Lanham [52] us. Cl IRIS/gigs], Amman Examiner Michae| J. Keenan 511 Int. Cl. 821] 11/00 Field Search... 72/405.

ABSTRACT: This disclosure relates to a press ofthe type provided with aligned plungers arranged to successively form a workpiece and having driving and restoring cams arranged to actuate the plungers through a crank mechanism having arms arranged in predetermined angular relationship and in engagement with the cams at all times.

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SHEET 3 OF 6 m aw WW A B W M v PRESS This invention relates to presses, and more particularly relates to a press of the type with a plurality of stations where workpieces are successively formed.

This invention provides a press of the type described adapted for high speed production with very precise control of die operations. Such characteristics are required in a press adapted to form and score workpieces such as tops of cans, including pull tabs. Such workpieces are usually quite thin, on the order of 0.009 inches and may be scored to a depth which is two-thirds of its thickness, leaving only a web of 0.003 inches.

To be economically acceptable, such pieces must be formed in high volume, and score'd to close tolerances in order that the pull tabs may be removed without too great or too small a force.

A press of the type to which this invention pertains is commonly referred to as a transfer press. Machines of this type are disclosed in U.S. Pat. Nos. 3,358,591 and 3,369,387. In such machines a plurality of forming plungers move vertically under the influence of a driving and lifting cam assembly. In one type of such machines each plunger has associated therewith a driving cam which acts on the plunger during a forming stroke, and a lifting cam which acts on a lifter arm or lever attached to the plunger to raise the driven plunger. Alternatively, all plungers may be carried in a reciprocating ram. In either type of machine, a plurality of aligned plunger: are driven to operate upon a plurality of workpieces which are transferred successively along the aligned plungers.

Such transfer is effected by a transfer mechanism comprising workpiece engaging means which grasp the workpieces and sequentially advance them after each series of forming strokes.

In high speed presses where the tolerances are very small the stability of the reciprocating plungers is quite important. Where the rotating driving cam operates against a cooperating follower on the end of a die-carrying plunger, such cam by virtue of its shape will exert nonradial thrusts against the follower which may tend to tilt the plunger relative to its guideway. Stable reciprocation of the plunger in its guideway also requires a guideway of adequate length and, therefore, the vertical distance between the overhead camshaft and the level of the workpiece forming zone must be efficiently utilized.

In the present invention, the effects of the nonrotational thrust on a cooperating follower are greatly minimized or eliminated by placing the driving cam follower on a laterally extending pivoted arm which takes the lateral thrust of the cam. The pivoted arm will reciprocate in an arcuate path and, therefore, is connected to the plunger by a link that oscillates with reciprocation of the plunger. To further minimize or eliminate the aforementioned problem, the plungers are formed hollow at least along a portion of their length and the link extends longitudinally into the hollow plunger in the region of its longitudinal center of gravity. With this arrangement, the presence of the link necessitates little, if any. reduction in the vertical dimension that is available for the plunger guideway. The link, together with its connection to the follower arm, is further so arranged as to prevent any rotational movement of a cylindrical plunger in its guideway and thus insures that a forming member carried by the plunger is cor rectly positioned with respect to a workpiece.

This invention further eliminates the space requirements demanded by a plunger lifter arm which has previously been positioned above the lifting cam, and in so doing greatly simplifies the lifter mechanism. The lifter arm or lever is arranged to be pivotal with the driving cam follower arm. With this arrangement the driving cam acts upon a cam follower on one arm to impart a driving force to the plunger and the lifting cam acts upon a cam follower on the lifter arm to pivot the entire crank arrangement and lift the plunger back to its raised position. The two arms of the crank are preloaded by llexurc of one of the two arms to provide constant pressure by the two followers against the two cams to control the operation of the plunger with essentially no backlash.

The present invention further provides a new and improved workpiece transfer actuating mechanism adapted for high speed operation.

An object of this invention is to provide a new and improved press of the type described.

Another object of this invention is to provide a new and improved plunger drive and lifting mechanism.

A further object of this invention is to provide a new and im proved combined plunger drive and lifting mechanism which utilizes a beilcrank-type mechanism in continuous contact with the driving and lifting cams.

A still further object of this invention is to provide a new and improved transfer mechanism for a machine of the type described.

The features of the invention which are believed to be novel are particularly pointed out and distinctly claimed in the coneluding portion of this specification. The invention, however, both as to its operation and organization together with further objects and advantages thereof may best be appreciated by reference to the following detailed description taken in conjunction with the drawings, wherein:

FIG. 1 is a front elevation of a press embodying the invention;

FIG. 2 is a view ofa transfer mechanism seen in the plane of lines 2-4 of FIG. 1;

FIG. 3 is an enlarged view, partially cut away, ofa portion of the press of FIG. 1;

FIG. 4 is a view seen in the plane oflines 4-4 of FIG. 3;

FIG. 5 is a view partially in section seen in the plane of lines 5-5 of FIG. 3',

FlG. 6 is a view partially in section seen in the plane of lines 6-6 of FIG. 4',

FIG. 7 is a view partially cut away of a lower die-carrying plunger;

FIG. 8 is a view seen in the plane oflines 88 of FIG. 3;

FIG. 9 is a view partially in section seen in the plane oflines 9-9 of FIG. 3;

FIG. 10 is a view in section seen in the plane of lines 10-10 of FIG. 3.

FIG. 11 is a partial side elevation of a press which is cut away to show another plunger and drive assembly embodying the invention;

FIG. 12 is a view seen in the plane oflines 12-12 of FIG. 11; and

FIG. I3 is a view seen in the plane oflines 13-13 of FIG. 11.

A press embodying the invention is generally indicated by the reference numeral 11 and comprises a base member 12 and upper crossmember or crown 13 carried by upright side frame members 14 and 15. Crown member 13 is of generally crosslike or box construction with a plurality of reinforcing crossmembers.

A camshaft 16 is rotatably supported in end bearing members 17 and a plurality of intermediate bearing support membeta 18 carried by and depending from crossmember 13. Camshaft 16 is driven from a motor 19 by a belt 20 and pulley 21 on camshaft 16. Camshaft 16 carries on the end thereof a tracked cam member 22 which operates a pivotally mounted lever 23 to actuate the transfer mechanism hereinafter described. A lower camshaft 24 is driven by camshaft 16 in timed relation thereto. A gear 25 on camshaft 16 in timed relation thereto. A gear 25 on camshaft 16 drives a pinion 26 on a shaft 27. Shaft 27 through a chain 28 drives shaft 29 and pinion 30 thereon. Pinion 30 meshes with a gear 31 which is mounted to camshaft 24. Camshaft 24 is rotatably supported in end-bearing members 32 carried on base 12 and a plurality of intermediate bearing support members 33.

A plurality of cam assemblies 35 are carried on shaft 16 and each is adapted to operate a plunger 36. Plungers 36 reciprocate in a guide member 37 which extends between upright sldc frame members 14 and 15.

Shaft 24 carries a plurality of cam assemblies 38 each adapted to operate a plunger 39 which reciprocates through die bed 40 extending between side frame members 14 and 15. Each of plungers 39 is adapted to cooperate with one of plungers 36 in a manner hereinafter described. A bolster 41 is carried on die bed 40, and is adapted to have workpiece holders or dies mounted thereon in a well-known manner.

The workpieces are moved between successive stations beneath the plungers by a reciprocating transfer bay 42. Transfer bar 42 comprises two longitudinal side bars 43 and 44 which slide in one or more guides 45. Side bars 43 and 44 are connected to push rods 46 which are reciprocally operated by lever 23. Rods 46 are slidably mounted in bracket 46a. Lever 23 is pivotally mounted about a pin 48 carried by a bracket 49 on side frame member 15, as more clearly shown in FIG. 3. At the upper end thereof lever 23 carries a pair of cam followers 50 which define a groove together with end member 51. This groove receives a continuous undulating track 52 defined on cam member 22. Track 52 is formed on cam member 22 so that when shaft [6 rotates track 52 will rock lever 23 in predetermined relation to rotation of cam 16 and operate a workpiece transfer bar. An adjustable extension member 53 is carried at the lower end of lever 23. Member 53 is pivotally connected to push rods 46 at 54.

Push rods 46 slide in spaced-apart bearings 60 carried in guide 61, mounted to upright frame member 15. Member 53 is pivotally connected about pin 54 carried by a link 55. Link 55 is, in turn, pivotally mounted about crossmember 58 interconnecting push rods 46'. Bracket 49, carrying pivot pin 48 is secured to frame member IS in guideways 59 (FIG. 9) to permit adjustment of bracket 49.

Reference is now made to FIGS. 3 and 4.

As shown in FIG. 4 each of the plungers 36 has a tool holder 36a adapted to have a punch or die 56 affixed thereto. Transfer bar 42 extends between the upper and lower plungers and engages and transfers workpieces between successive dies 57 mounted to bolster 41, as more clearly shown in FIG. 3.

The continuous track 52 on cam member 22 is of predetermined configuration to cause the desired periodic reciprocation of lever 23 to operate transfer bar 42 in timed relation to the operation of the upper and lower plungers.

As more clearly shown in FIG. 2, the transfer bar is provided with workpiece-engaging elements 420 to pick up the workpieces at the various stations of the press. As is well known to those versed in the art, stock may be fed in and an initial blanking step performed at the station indicated at A in FIGS. 1 and 2. Subsequently. the finished workpiece is unloaded in the area indicated at B. At station A, stock (not shown) is periodically advanced to permit blanks to be punched from the stock. One pair of the transfer elements 42a from transfer bar 42 is adapted to move the blanks from the first station A to the succeeding station, the other transfer elements then sequentially move the work in each forming station. The construction details of the transfer bar actuating mechanism are more clearly set forth in FIGS. 8, 9 and I0.

The guide member 37 has upper and lower spaced-apart guideways 37a and 37b which extend from a generally boxlike frame or girder 370 having inwardly directed portions or flanges 37d which bolt to side support 14, as shown, and at the other end thereof to side frame 15. The guideways 37a and 37b have passages defined therethrough which receive sleeves 36b and 36: therein. Plunger 36 then moves linearly in sleeves 36b and 36c. Each of the plungers 36 is operated by a cam assembly 35 on shaft 16 through a crank member 62. Each of the cam assemblies 35 includes a driving cam 63 and a lifting cam 63a. The two cams 63 and 630 may be formed integrally.

The crank arrangement 62 is similar to a bellcrank in that both arms pivot about a fixed point defined by a shaft 64. Shaft 64 is carried in support member 65 mounted to girder 37c having upright portions 66 which receive the ends of the adjacent shafts 64. The crank assemblies 62 comprise a first lever 67 carrying a follower in the form of a roller 68 which follows driving cam 63. An upwardly extending lever 69 carries a follower roller 70 arranged in contact with a lifting cam 63a. The levers 69 are rotatable about shaft 64 on bearings 71. The bases of levers 69 are formed with annular surfaces 72 which receive thereon the hub 73 of lever 67. As thus far described, the levers 67 and 69 are relatively pivotable. The levers 67 and 69 are arranged in a predetermined fixed angular relationship to one another by means of bolts 75 which extend through webs 76 on lever 69 into extended portions 77 of lever 67. The bolts 75 connect the two levers which would otherwise be independently pivotal so that a single pivotal structure in the nature of a bellcrank is provided. The levers 67 and 69 are preloaded in flexure by bolt 75 acting through spherically seated shims 84 to bias the levers toward each other and maintain at least one of the roller followers in constant pressure contact with its cam at all times. This essentially eliminates backlash in movement of the plungers.

Each of the plungers 36 is made hollow or tubular to receive a link 78. Link 78 at the upper end thereof engages and is attached to a squared off portion 79 of a pin 80 carried on an extension or arm of lever 67. The upper end of link 78 is secured to portion 79 as by means of a bolt 81. The lower end of link 78 is pivotally connected to pin 82 carried by plunger 36.

In operation, as shaft 16 is rotated in the direction shown in FIG. 4 it will transmit a force through cam follower 68 which rotates crank 62 in a counterclockwise direction and drives plunger 36 downwardly in a forming stroke. As cam 63 continues to rotate, plunger 36 will reach the bottom of its stroke and the tool carried on holder 36a will perform its forming operation. For continued rotation of camshaft l6, cam 63a will impart a force to cam follower rollers 70 carried on levers 69 and rotate crank 62 in a clockwise direction. When this oc curs, lever 67 through pin 79 will lift link 78 and plunger 36 towards its uppermost position.

The arrangement of crank 62 is such that no clearance for a lifter or cam follower above shaft I6 is required.

Each cam assembly 35 will be oriented on shaft 16 in a predetermined angular relationship with the other cams in order to achieve the desired effect on the workpieces.

The driving and restoring mechanism for the lower plungers 39 may be made similar to that of the upper plungers 36. In FIG. 7 each of the lower cam assemblies 38 comprises a driving cam and a restoring cam 91. The plunger 39 slides in a defined guideway in die bed 40. A crank assembly 92 is pivotally mounted to an extension of die bed 40. Each crank assembly comprises a driving arm 93 and a restoring arm 94. Each of arms 93 and 94 carry roller followers 95 and 96 and are angularly adjusted with respect to each other as by means of a bolt 97 in the same manner as described in conjunction with crank 62. A link 98 is pivotally connected at its upper end at 99 to plunger 39 and is connected at its lower end to a squared off portion 100 on a pin carried by arm 93.

The operation of the mechanism of FIG. 7 with respect to plunger 39 will be the same as the operation of crank 62 with respect to plunger 36, the only significant difference being that the plunger 39 moves upwardly on a driving stroke while the plunger 36 moves downwardly on a driving stroke.

Where the press may be arranged for operation of stock in strip form, the strip may be fed into station A for blanking. As the stock is fed in it would be blanked by the plunger 36 against a die 57 and simultaneously the cooperating plunger 39 would form the lower portion of the blank stock, if that be the desired mode of operation at station A. Subsequently, as camshaft 16 is rotated, lever 23 follows track 52 on cam 22 and through push rods 46 advances transfer bar 42 where the elements 42a pick up the blanked workpiece and transfer it to the next succeeding die on bolster 41. This transfer actuating mechanism is simple in construction yet extremely reliable. From the shaft 16 through the cam 22, lever 23 and output of push rods 46 it provides maximum rigidity coupled with minimum inertia and is therefor well suited for high operating speeds.

Dependent upon the desired mode of operation at each station, either or both of plungers 36 and 39 may carry a forming tool.

Upon transfer of the workpieces to the next succeeding stations, the plungers commence their driving stroke to perform the next forming operation.

Where very high forming pressures are involved, the forming or driving strokes of the plungers may be displaced a few degrees so that all forming pressure is not transmitted to the frame simultaneously.

Another embodiment of the invention is shown in FIGS. 11, I2 and 13. In this embodiment, the plunger 39' is driven by a modified lifter and return mechanism,

Driving and restoring earns 90 and 91 are mounted to the shaft 24' which in this instance is displaced laterally with respect to the position shown in FIG. 7. Cam 90 acts upon a roller follower 103 and cam 91 acts on a roller follower 104 which are mounted to levers 105 and 106 ofcrank 107. Crank 107 has an integral extending arm 108 which is received within a slot 109 in plunger 39'. Mounted to the end of lever 108 is a member 110 having upper and lower bearing surfaces which are defined on the perimeter of a cylinder. The bearing surfaces act against upper and lower inserts 111 and 112 in recess or slot 109. As such, the bearing surfaces of member 110 are always in engagement with plunger 39' through the inserts 111 and 112.

The crank 107 is rockably mounted to a shaft 113 supported at spaced-apart intervals by supports 114 carried on the frame of the machine.

Shaft 24' with cams 90 and 91 thereon is also carried in supports 114. The supports 114 are further mounted to a longitudinal crossmember 115 extending between side frames 14 and 15.

The arms 105 and 106 are so arranged that the axes of the rollers 103 and 104 define an angle of 90 with the axis of the shaft 113. This facilitates the manufacture of the apparatus and further minimizes the space requirements for the mechanism shown in FIGS. 11-13.

In operation, as shaft 24' is rotated, cam 90 acts upon follower 103 pivoting it clockwise about shaft 113. This transmits a driving force to plunger 39 and moves it upwardly. As plunger 39 reaches its uppermost position, cam 91 will begin acting upon follower 104 and will accordingly rotate arm 106 in a counterclockwise direction about shaft 113. Arm 108 will then drive plunger 39' in a restoring stroke.

Functionally, this arrangement is equivalent to that shown in FIGS. 4 and 7.

Accordingly, the objects of the invention set forth as well as those made apparent from the foregoing disclosure are efficiently attained. While a preferred embodiment of the invention has been set forth for purposes of disclosure, modifications thereto as well as other embodiments which do not depart from the spirit and scope of the invention may occur to others skilled in the art Accordingly, the appended claims are intended to cover all embodiments of the invention and modifications of the disclosed embodiments which do not de part from the spirit and scope ofthe invention.

What I claim is:

1. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a plunger, means defining a guideway for said plunger, first and second cams mounted to said shaft, first and second levers pivotally mounted at one end thereof about a common axis, said levers carrying cam followers at the other ends thereof arranged to contact said first and second cams respectively, and means attached to one of said levers toward the follower end thereof and to said plunger to impart reciprocatory force to said plunger as said cams are rotated and act on said cam followers.

2. In a press ofthe type described, a frame, a shaft rotatably mounted in said frame, a plunger hollow along at least a portion of its length, means defining a guideway for said plunger, first and second cams mounted to said shaft, first and second levers pivotally mounted at one end thereof about a common axis, said levers carrying cam followers at the other ends thereofarranged to contact said first and second cams, respec' tively, a link attached to one of said levers adjacent the follower end thereof and to said plunger, said link extending into said hollow plunger substantially axially thereof and eing connected thereto.

3. The press of claim 2, wherein said link is connected to a pin pivotally carried by said one of said levers, said pin being provided with flats engaged by said link to prevent relative movement of said pin and said link, said link being pivotally connected at the other end thereof to a pin carried by said plunger.

4. The press of claim 1 wherein said levers are in predetermined fixed angular relationship.

5. The press of claim 4 wherein said first and second levers are preloaded in flexure to bias the levers toward each other to maintain the followers carried thereby in constant pressure contact with the cams.

6. The press of claim I wherein said guideway is defined in two vertically spaced-apart portions.

7. The press of claim 4 where said levers define an angle of substantially or less.

8. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a cam on said shaft. a forming member, guide means defining a guideway for said forming member, a lever pivotally mounted on said frame at one end thereof, a follower carried on the other end of said lever, and means attached to said lever toward the follower end thereof and to said forming member to impart reciprocatory movement to said forming member as said cam is rotated and acts on said follower.

9. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a plunger, means defining a guideway for said plunger, first and second cams mounted to said shaft, first and second levers in fixed angular relation to each other and pivotally mounted at one end thereof about a common axis, said levers carrying cam followers at the other ends thereof arranged to be contacted by said first and second cams, respectively and an arm in fixed relation to and actuated by movement of said levers, said plunger having a slot defined therein intermediate the ends thereof terminating in upper and lower surfaces, a force-transmitting member carried on said arm and having upper and lower surfaces which are defined on the surface of a cylinder, said surfaces of said force transmitting member and said slot-terminating surfaces being in contact.

10. The apparatus of claim 9 wherein said levers define in angle ofsubstantially 90 with said common axis.

11. The apparatus of claim 9 wherein said levers define an angle of 90 or less with said common axis.

12. The apparatus of claim 9 wherein said levers and said arm are formed in a unitary structure. 

1. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a plunger, means defining a guideway for said plunger, first and second cams mounted to said shaft, first and second levers pivotally mounted at one end thereof about a common axis, said levers carrying cam followers at the other ends thereof arranged to contact said first and second cams respectively, and means attached to one of said levers toward the follower end thereof and to said plunger to impart reciprocatory force to said plunger as said cams are rotated and act on said cam followers.
 2. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a plunger hollow along at least a portion of its length, means defining a guideway for said plunger, first and second cams mounted to said shaft, first and second levers pivotally mounted at one end thereof about a common axis, said levers carrying cam followers at the other ends thereof arranged to contact said first and second cams, respectively, a link attached to one of said levers adjacent the follower end thereof and to said plunger, said link extending into said hollow plunger substantially axially thereof and being connected thereto.
 3. The press of claim 2, wherein said link is connected to a pin pivotally carried by said one of said levers, said pin being provided with flats engaged by said link to prevent relative movement of said pin and said link, said link being pivotally connected at the other end thereof to a pin carried by said plunger.
 4. The press of claim 1 wherein said levers are in predetermined fixed angular relationship.
 5. The press of claim 4 wherein said first and second levers are preloaded in flexure to bias the levers toward each other to maintain the followers carried thereby in constant pressure contact with the cams.
 6. The press of claim 1 wherein said guideway is defined in two vertically spaced-apart portions.
 7. The press of claim 4 where said levers define an angle of substantially 90* or less.
 8. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a cam on said shaft, a forming member, guide means defining a guideway for said forming member, a lever pivotally mounted on said frame at one end thereof, a follower carried on the other end of said lever, and means attached to said lever toward the follower end thereof and to said forming member to impart reciprocatory movement to said forming member as said cam is rotated and acts on said follower.
 9. In a press of the type described, a frame, a shaft rotatably mounted in said frame, a plunger, means defining a guideway for said plunger, first and second cams mounted to said shaft, first and second levers in fixed angular relation to each other and pivotally mounted at one end thereof about a common axis, said levers carrying cam followers at the other ends thereof arranged to be contacted by said first and second cams, respectively and an arm in fixed relation to and actuated by movement of said levers, said plunger having a slot defined therein intermediate the ends thereof terminating in upper and lower surfaces, a force-transmitting member carried on said arm and having upper and lower surfaces which are defined on the surface of a cylinder, said surfaces of said force transmitting member and said slot-terminating surfaces being in contact.
 10. The apparatus of claim 9 wherein said levers define an angle of substantially 90* with said common axis.
 11. The apparatus of claim 9 wherein said levers define an angle of 90* or less with said common axis.
 12. The apparatus of claim 9 wherein said levers and said arm are formed in a unitary structure. 